Relationship between excitation and inhibition underlying size tuning and contextual response modulation in the cat primary visual cortex
Relationship between excitation and inhibition underlying size tuning and contextual response modulation in the cat primary visual cortex
复制标题
DOI：
10.1523/jneurosci.3852-03.2004
复制
发表时间：
2004-02-11
影响因子：
5.3
通讯作者：
Sato, H
中科院分区：
文献类型：
--
作者：
Ozeki, H;Sadakane, O;Sato, H
在初级视皮层（V1），单神经元对置于经典感受野（CRF）的光栅刺激的反应被CRF周围的类似刺激抑制。为了评估周围抑制的输入机制，我们测试了离子电渗给药的GABA（A）受体拮抗剂，bicuculline methiodide（BMI），对麻醉猫的46个V1神经元的影响。首先，通过改变光栅贴片的大小，研究了每个神经元在有或没有BMI给药的情况下的刺激大小调谐曲线。在BMI给药期间，标准化尺寸调谐曲线的形状没有显著变化。其次，检查环绕抑制对环绕光栅的取向的依赖性。在对照组中，环绕抑制显示出清晰的方向调谐，其峰值在与CRF响应的最佳方向相同的方向。BMI管理没有改变环绕抑制的方向依赖性。我们还估计了兴奋和抑制的大小和方向调谐的环绕抑制的相对贡献。得出的结论是，皮层的兴奋和抑制是很好的平衡，具有类似的调谐配置文件的刺激大小和方向的环绕光栅。此外，周围刺激V1神经元抑制CRF反应的神经元在外侧膝状体。这些结果表明，环绕抑制主要不是由于皮层内抑制，而是因为减少丘脑皮质输入，驱动皮层兴奋和抑制，以及随后减少皮层兴奋性相互作用。
In the primary visual cortex (V1), the single-neuron response to a grating stimulus placed in the classical receptive field (CRF) is suppressed by a similar stimulus presented in the CRF surround. To assess the input mechanism underlying the surround suppression, we tested the effects of iontophoretically administered GABA(A)-receptor antagonist, bicuculline methiodide (BMI), for the 46 V1 neurons in anesthetized cats. First, the stimulus-size tuning curves were studied, with or without BMI administration, for each neuron by changing the size of the grating patch. During the BMI administration, the shape of the normalized size tuning curve did not change considerably. Second, the dependency of surround suppression on the orientation of the surround grating was examined. In the control, the surround suppression showed the clear orientation tuning that peaked at an orientation the same as the optimal orientation of the CRF response. The BMI administration did not change the orientation dependency of surround suppression. We also estimated the relative contribution of excitation and inhibition to the size and orientation tuning of surround suppression. It was concluded that cortical excitation and inhibition were well balanced, having similar tuning profiles for both stimulus size and orientation of the surround grating. Furthermore, surround stimuli used for V1 neurons suppressed the CRF response of neurons in the lateral geniculate nucleus. These results suggest that surround suppression is not primarily attributable to the intracortical inhibition, but because of a reduction of thalamocortical inputs, which drive the cortical excitation and inhibition, and a subsequent decrease in the cortical excitatory interactions.